File extensions – definition and basic information


File extensions are the integral parts of the files that are on each computer. Often, when working on a computer, we encounter a wide range of files, such as docx, ppt, part, mp3 or rmvb. We realize that they are there – but we often do not know what they are for on our computer.

File extension, also known as the filename extension is a suffix added to the name of a computer file, usually consisting of a number of characters placed after the last dot in the filename, which gives us information about its coding. In other words a file extension is a file format. It allows the operating system (e.g. Windows) to recognize what program it should try to open the file.

In the table below you will find a random selection of popular file extensions.


File extension The full name of the file Category

CUE file extension

Cue Sheet File

Disk Image Files

GED file extension

GEDCOM Genealogy Data File

Data Files

MP3 file extension

MP3 Audio File

Audio Files

MP4 file extension

MPEG-4 Video File

Video Files

MPA file extension

MPEG-2 Audio File

Audio Files

PPS file extension

PowerPoint Slide Show

Data Files

PPTX file extension

PowerPoint Open XML Presentation

Data Files

RPM file extension

Red Hat Package Manager File

Compressed Files

SDF file extension

Standard Data File

Data Files

THM file extension

Thumbnail Image File

Raster Image Files

TIFF file extension

Tagged Image File Format

Raster Image Files

VCF file extension

vCard File

Data Files

WAV file extension

WAVE Audio File

Audio Files

XML file extension

XML File

Data Files

ZIPX file extension

Extended Zip File

Compressed Files